redis记录用户在线状态+活跃度

1.记录用户在线状态

redis的Bitmap记录用户在线状态

• 使用一个大的Bitmap,每个bit位对应一个用户ID
• bit值1表示在线,0表示离线
• 用户ID与bit位的映射关系: bit位置 = 用户ID % bitmap容量

具体实现:

# 用户上线时,设置对应bit为1
SETBIT online_users {user_id} 1

# 用户下线时,设置对应bit为0  
SETBIT online_users {user_id} 0

# 判断用户是否在线
GETBIT online_users {user_id}

# 获取当前在线用户数量
BITCOUNT online_users

# 批量获取在线用户列表
# 每次获取一个字节(8位)的数据
for i in range(0, max_user_id, 8):
    byte = GETRANGE online_users i i+7
    # 解析byte中的每一位,位为1的即为在线用户

1.1优化策略

按业务分片

# 可以按照业务线划分不同的bitmap
SETBIT online_users:game {user_id} 1
SETBIT online_users:chat {user_id} 1

# 统计特定业务的在线用户
BITCOUNT online_users:game

时间分片

# 按天记录用户在线状态
SETBIT online_users:{date} {user_id} 1

# 统计最近7天的日活用户(使用BITOP OR合并)
BITOP OR online_users_7days 
    online_users:20240212
    online_users:20240211
    ...
    online_users:20240206

容量优化

• 每个bitmap最大512MB,可存储40亿用户状态
• 当用户量超大时,可以分片存储:

# 用户ID按范围分片
SETBIT online_users:0 {user_id % 1000000} 1
SETBIT online_users:1 {user_id % 1000000} 1

1.2java代码示例

// 1. 配置类
@Configuration
public class RedisConfig {
    @Bean
    public RedisTemplate redisTemplate(RedisConnectionFactory connectionFactory) {
        RedisTemplate template = new RedisTemplate<>();
        template.setConnectionFactory(connectionFactory);
        template.setKeySerializer(new StringRedisSerializer());
        template.setValueSerializer(new StringRedisSerializer());
        return template;
    }
}

// 2. 用户在线状态服务
@Service
@Slf4j
public class UserOnlineStatusService {
    @Autowired
    private RedisTemplate redisTemplate;
    
    private static final String ONLINE_KEY_PREFIX = "user:online:";
    private static final int EXPIRE_DAYS = 7; // 数据保留7天
    
    /**
     * 设置用户在线
     */
    public void setUserOnline(Long userId, String bizType) {
        try {
            String key = buildKey(bizType, LocalDate.now());
            redisTemplate.opsForValue().setBit(key, userId, true);
            // 设置过期时间
            redisTemplate.expire(key, EXPIRE_DAYS, TimeUnit.DAYS);
        } catch (Exception e) {
            log.error("Failed to set user online status: userId={}, bizType={}", userId, bizType, e);
            throw new RuntimeException("Failed to set user online status", e);
        }
    }
    
    /**
     * 设置用户离线
     */
    public void setUserOffline(Long userId, String bizType) {
        try {
            String key = buildKey(bizType, LocalDate.now());
            redisTemplate.opsForValue().setBit(key, userId, false);
        } catch (Exception e) {
            log.error("Failed to set user offline status: userId={}, bizType={}", userId, bizType, e);
            throw new RuntimeException("Failed to set user offline status", e);
        }
    }
    
    /**
     * 批量设置用户在线状态
     */
    public void batchSetUserOnline(List userIds, String bizType) {
        String key = buildKey(bizType, LocalDate.now());
        try {
            for (Long userId : userIds) {
                redisTemplate.opsForValue().setBit(key, userId, true);
            }
            redisTemplate.expire(key, EXPIRE_DAYS, TimeUnit.DAYS);
        } catch (Exception e) {
            log.error("Failed to batch set user online status: userCount={}, bizType={}", 
                userIds.size(), bizType, e);
            throw new RuntimeException("Failed to batch set user online status", e);
        }
    }
    
    /**
     * 判断用户是否在线
     */
    public boolean isUserOnline(Long userId, String bizType) {
        try {
            String key = buildKey(bizType, LocalDate.now());
            return Boolean.TRUE.equals(redisTemplate.opsForValue().getBit(key, userId));
        } catch (Exception e) {
            log.error("Failed to check user online status: userId={}, bizType={}", userId, bizType, e);
            throw new RuntimeException("Failed to check user online status", e);
        }
    }
    
    /**
     * 获取当前在线用户数量
     */
    public long getOnlineUserCount(String bizType) {
        try {
            String key = buildKey(bizType, LocalDate.now());
            return redisTemplate.execute((RedisCallback) con -> con.bitCount(key.getBytes()));
        } catch (Exception e) {
            log.error("Failed to get online user count: bizType={}", bizType, e);
            throw new RuntimeException("Failed to get online user count", e);
        }
    }
    
    /**
     * 获取指定用户列表中的在线用户数量
     */
    public long getOnlineUserCount(List userIds, String bizType) {
        String key = buildKey(bizType, LocalDate.now());
        long count = 0;
        try {
            for (Long userId : userIds) {
                if (Boolean.TRUE.equals(redisTemplate.opsForValue().getBit(key, userId))) {
                    count++;
                }
            }
            return count;
        } catch (Exception e) {
            log.error("Failed to get online user count for specific users: userCount={}, bizType={}", 
                userIds.size(), bizType, e);
            throw new RuntimeException("Failed to get online user count", e);
        }
    }
    
    /**
     * 获取在线用户列表
     * @param start 起始用户ID
     * @param end 结束用户ID
     */
    public List getOnlineUsers(String bizType, long start, long end) {
        List onlineUsers = new ArrayList<>();
        String key = buildKey(bizType, LocalDate.now());
        try {
            for (long userId = start; userId <= end; userId++) {
                if (Boolean.TRUE.equals(redisTemplate.opsForValue().getBit(key, userId))) {
                    onlineUsers.add(userId);
                }
            }
            return onlineUsers;
        } catch (Exception e) {
            log.error("Failed to get online users: bizType={}, start={}, end={}", 
                bizType, start, end, e);
            throw new RuntimeException("Failed to get online users", e);
        }
    }
    
    /**
     * 统计今日在线过的用户数量（活跃用户）
     */
    public long getDailyActiveUserCount(String bizType) {
        try {
            String key = buildKey(bizType, LocalDate.now());
            return redisTemplate.execute((RedisCallback) con -> con.bitCount(key.getBytes()));
        } catch (Exception e) {
            log.error("Failed to get daily active user count: bizType={}", bizType, e);
            throw new RuntimeException("Failed to get daily active user count", e);
        }
    }
    
    /**
     * 统计指定日期范围内的活跃用户数量（去重）
     */
    public long getActiveUserCountByDateRange(String bizType, LocalDate startDate, LocalDate endDate) {
        try {
            List keys = new ArrayList<>();
            LocalDate currentDate = startDate;
            while (!currentDate.isAfter(endDate)) {
                keys.add(buildKey(bizType, currentDate));
                currentDate = currentDate.plusDays(1);
            }
            
            // 使用OR操作合并多个bitmap
            String destKey = String.format("%s:temp:%s:%s", 
                ONLINE_KEY_PREFIX, startDate, endDate);
            redisTemplate.execute((RedisCallback